DENVER - The letters may look like they're from an airline with claims you've been awarded tickets, but a 9Wants to Know undercover investigation reveals they're part of a marketing gimmick for travel agencies.

"It is a little misleading because they use familiar airlines," said US Postal Inspector JoJan Henderson. "We are seeing more complaints from people who don't believe they're getting what they thought they would."

Hundreds of viewers have told 9News they have received the letters with a "US Airlines," or "Delta Skyrewards," letterhead.

9Wants to Know called a number on the "US Airlines" letter. An operator answered and said a voucher for the airline tickets would be provided after attending a 90 minute presentation by a Denver travel agency.

9Wants to Know attended the presentation in an office building near Mexico and Colorado with a hidden camera. Travel agency employees are seen on the undercover video trying to convince attendees to spend $18,000 on a travel club membership.

"It's $18,000 once for you and your family for the rest of your life," one of the employees said on video.

Being a member means access to vacation lodging at $159 per week at locations all over the world, according to one of the employees.

A credible travel agency?

While employees are seen on undercover video claiming to be a business with an "A+" accredited rating with the Better Business Bureau, 9Wants to Know found that is not entirely true.

Employees claimed several times they were with Global Connections, based in Kansas. However, a sign on their office door says "Global Travel Network."

9Wants to Know confirmed the agency is operated by Global Travel Network, which had its BBB accreditation revoked because of complaints, many of which refer to the airline tickets letter.

The owner of Global Travel Network, Scott Nichols, declined to comment with 9Wants to Know about this report, but said he would review how his employees are trained in the Denver office.

Megan Herrera with the Denver/Boulder BBB calls the use of another business's rating wrong. "It's very misleading and concerning to us because it's basically a form of deceptive sales practices," Herrera said.

A spokesperson for Global Connections says Global Travel Network is authorized to sell its products as a "distributor" but that the two are not the same company.

Global Connections in Kansas has an "A+" rating, but is able to keep the grade despite 103 complaints over the last three years. Some of the complaints are about the airline tickets letters.

The BBB says Global Connections is able to keep it's A+ accreditation because it makes an effort to resolve customer complaints. The number of complaints compared to a company's size is also a factor.

Both Global Connections and Global Travel Network denied responsibility for the US Airlines letters and claimed an "outside" marketing company is responsible.

"I didn't get what I was promised," Shelby Lawson told 9Wants to Know during an interview about the letters. Lawson complained about Global Travel Network to the BBB after filling out the paperwork. "There was a cost of 50 dollars per ticket just to get the voucher."

A ticket certificate given to 9Wants to Know after the presentation contains fine print saying the applicant must send in $50 dollars per ticket in money orders for taxes and fees.

The "US Airlines" company in Wyoming

Operators who answer the 800 number on the letters will not reveal exactly who they work for and instead claim they are just marketing for local travel agencies.

After numerous attempts to get the name of their company and after leaving several messages on a "legal department" voicemail, 9Wants to Know eventually confirmed the operators work for Tier3 Marketing in Scottsdale, AZ.

A Tier3 supervisor told 9Wants to Know his company is not responsible for the letters but that they take in calls for a company named "US Airlines, LLC" in Wyoming.

9Wants to Know found an office in Cheyenne that was listed as the official address for "US Airlines, LLC" according to business registration information from the Wyoming Secretary of State's office.

After talking with a woman at the office who claimed not to know anything about "US Airlines," 9Wants to Know received an email from Travel Club Marketing Brokers, which claimed ownership of the "US Airlines, LLC" name.

TCMB General Manger Anthony Martin said in an email to 9Wants to the Know the "US Airlines moniker" refers to "all US airlines" and that the name is used to promote travel agencies.

"Our intent is to generate enough interest by the letter recipient for them to call one of our call centers," Martin wrote. "We have mailed tens of millions of these pieces for all sorts of businesses in the US; Travel Clubs, Timeshares, Car Dealers, Wholesale Buying Clubs, Home Improvement Companies, etc. There are, at best, a handful of concerns by individuals."

During the undercover encounter with Global Travel Network a sales woman was recorded on camera saying, "We just bribe people to come in here with vacations to let you know what we do."

Martin did not respond to emails asking if his company also registered "Delta Skyrewards, LLC" which shares the same address as "US Airlines."

US Airways calls the letters "fraudulent" in a warning on its website.

Meticulous paperwork and money for tickets

Amid its newsgathering efforts for this report, 9Wants to Know filled out the certificate for tickets.

After filling out paperwork and sending $104 to a different travel marketing company in Florida, 9Wants to Know received more paperwork to fill out from a company called Passport to Travel.

After filling out the paperwork that contained numerous black-out dates for travel, 9Wants to Know received two electronic United tickets for Phoenix.

Travel Club Marketing acknowledged it was aware 9Wants to Know applied for the tickets and received them.

"I understand you have been ticketed," Anthony Martin wrote in an email. "I request that [sic] include that in your article. Also note that TCM Brokers will aggressively protect its reputation. Any erroneous information reported buy you or anyone at channel nine [sic] will be pursued legally."

Martin said in the email the companies his company represents have "hundreds of thousands" of happy customers.

US Postal inspectors urge consumers to file complaints with their office if they feel they've been defrauded by the airline tickets letters.

Have a comment or tip for investigative reporter Jeremy Jojola? Call him at 303-871-1425 or e-mail him jeremy.jojola@9news.com